Lesson 3: Blood Sugar

Question 1

The Pancreas

Answer 1

The Islets of Langerhans in the pancreas
produce insulin (β cells) an glucagon (α
cells).

Insulin and glucagon are amino acid derived hormones that control the amount of glucose in the bloodstream.

Insulin and glucagon are known as
antagonistic hormones because they have opposite physiological effects but work together to maintain the same system.

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Question 2

Blood Glucose Levels

Answer 2

Normal blood glucose stays in a narrow
range of between 4 mmol dm-3 to 8 mmol dm-3.

This is maintained so that the osmotic
balance of the blood is maintained while
ensuring that the cells receive sufficient
glucose for cellular respiration.

Glucose levels are higher after meals and usually at their lowest first thing in the morning.

Question 3

Maintaining Glucose Levels

Answer 3

An increase in glucose levels is sensed by the β cells in the pancreas.

This rise in blood sugar causes the β cells to secrete insulin into the
bloodstream

The presence of insulin in the blood causes the liver and muscle cells to take
up more glucose and convert it into glycogen and fat.

This increased uptake causes glucose levels to fall.

Decreased glucose levels are sensed by the α cells in the pancreas.

This drop in glucose levels causes the α cells to secrete glucagon into the
bloodstream

The presence of glucagon in the blood causes the liver to hydrolyse glycogen
to produce glucose, which is released into the blood.

This glucose release causes glucose levels to rise

Question 4

Diabetes

Answer 4

Type I

The β cells do not produce insulin

Usually diagnosed in childhood

10% of diabetes is type I

Cased by autoimmune disease

Type II

Body cells fail to respond to insulin

Usually diagnosed after childhood

90% of Diabetes is type II

Caused by increased weight and poor diet